Hoff, Daniel D. Von

276 Background: BL-8040 is a novel CXCR4 antagonist being developed for multiple oncology indications. Preclinical studies demonstrated that BL-8040 increases the number of immune cells in peripheral blood and promotes CD8+ T cell infiltration into orthotropic pancreatic mouse tumors, reducing tumor load. BL-8040 is being evaluated in a Phase 2a, multicenter, open label trial in patients with metastatic pancreatic cancer (the COMBAT study). Patients are undergoing a 5-day period of monotherapy in which they receive daily doses of BL-8040, followed by 21-day cycles in which patients receive one dose of pembrolizumab and 3 doses/week of BL-8040 until disease progression or discontinuation. To date, 32 patients have been enrolled. Methods: On Day 1 and Day 5, blood samples were taken at pre- and post-dosing, to evaluate peripheral immune cell subset frequency by flow cytometry. In addition, core biopsies were taken from liver metastases, where possible, to assess immune cell infiltration into tumors and the tumor microenvironment (TME). Results: Here we present interim PD biomarker data from the BL-8040 monotherapy portion of the trial. Flow cytometry shows that BL-8040 monotherapy caused an approximately two-fold reduction in frequency of peripheral T regulatory cells, but had no effect on the frequency of T cells, NKT cells or cell populations that contain B cells (CD3- CD56-). Additionally, BL-8040 remained bound to CXCR4 on peripheral immune cells throughout the period of monotherapy. Analysis of available biopsies (N = 7) shows an up to 15-fold increase in the CD3+ population, and up to two-fold increase of CD8+ cells, in the tumor periphery and TME of 43% (3/7) of the patients after five days of BL-8040 monotherapy compared to baseline. Conclusions: In summary, the PD biomarker results in humans support the proposed mechanism of action for BL-8040 that was based on preclinical mouse models. Analysis of tumor biopsies is ongoing, with an emphasis on investigating the effects of BL-8040 on tumor-resident immune cells and the TME. Clinical trial information: NCT02826486.

4109 Background: Prognostic nomograms have been developed in various cancers, including ovarian, breast, and gastrointestinal; however, there is limited information on nomograms in MPC. The large, phase 3 MPACT study of nab-P + Gem vs Gem alone for the treatment of MPC provides a robust database for the development of a nomogram to predict OS using baseline patient variables. Methods: A multivariable Cox model was created from MPACT data using factors that were significantly predictive of OS in univariable analysis or considered clinically important (stepwise selection to remain in model). From the Cox model, a nomogram was derived that assigned points equal to the weighted sum of relative significance of each variable. The nomogram was internally validated using bootstrapping, a concordance index (c-index), and calibration plots. Results: Data from all 861 pts were used. Seven of the 34 considered variables were retained in the multivariable analysis (Table; all factors significant at the P < 0.01 level, except for analgesic use [ P = 0.07]). The resulting nomogram was able to distinguish low (n = 216), medium (n = 430), and high (n = 215) risk groups (c-index: 0.69; CI: 0.67-0.71) with median OS values of 12.9, 8.2, and 3.7 months, respectively. Calibration curves showed that the nomogram’s predicted probabilities were mostly consistent with observed probabilities for 6-, 9-, and 12-month OS. Conclusions: Treatment arm, Karnofsky performance status (KPS), neutrophil-to-lymphocyte ratio (NLR), albumin level, sum of longest tumor diameters (SLD), and presence of liver metastasis were the key predictors of OS. This nomogram, which will be presented in visual format in the final presentation, may help physicians and pts make informed treatment decisions. Clinical trial information: NCT00844649. [Table: see text]

88 Background: BL-8040 is a novel CXCR4 antagonist being developed for multiple oncology indications. Preclinical studies demonstrated that BL-8040 increases the number of immune cells in peripheral blood and promotes CD8+ T cell infiltration into orthotropic pancreatic mouse tumors, reducing tumor load. BL-8040 is being evaluated in a Phase 2a, multicenter, open label trial in patients with metastatic pancreatic cancer (the COMBAT study). Patients are undergoing a 5-day period of monotherapy in which they receive daily doses of BL-8040, followed by 21-day cycles in which patients receive one dose of pembrolizumab and 3 doses/week of BL-8040 until disease progression or discontinuation. To date, 32 patients have been enrolled. Methods: On Day 1 and Day 5, blood samples were taken at pre- and post-dosing, to evaluate peripheral immune cell subset frequency by flow cytometry. In addition, core biopsies were taken from liver metastases, where possible, to assess immune cell infiltration into tumors and the tumor microenvironment (TME). Results: Here we present interim PD biomarker data from the BL-8040 monotherapy portion of the trial. Flow cytometry shows that BL-8040 monotherapy caused an approximately two-fold reduction in frequency of peripheral T regulatory cells, but had no effect on the frequency of T cells, NKT cells or cell populations that contain B cells (CD3- CD56-). Additionally, BL-8040 remained bound to CXCR4 on peripheral immune cells throughout the period of monotherapy. Analysis of available biopsies (N = 7) shows an up to 15-fold increase in the CD3+ population, and up to two-fold increase of CD8+ cells, in the tumor periphery and TME of 43% (3/7) of the patients after five days of BL-8040 monotherapy compared to baseline. Conclusions: In summary, the PD biomarker results in humans support the proposed mechanism of action for BL-8040 that was based on preclinical mouse models. Analysis of tumor biopsies is ongoing, with an emphasis on investigating the effects of BL-8040 on tumor-resident immune cells and the TME. Clinical trial information: NCT02826486.

Abstract Taselisib is a potent and selective tumor growth inhibitor through PI3K pathway suppression. Thirty-four patients with locally advanced or metastatic solid tumors were treated (phase I study, modified 3+3 dose escalation; 5 cohorts; 3–16 mg taselisib once-daily capsule). Taselisib pharmacokinetics were dose-proportional; mean half-life was 40 hours. Frequent dose-dependent, treatment-related adverse events included diarrhea, hyperglycemia, decreased appetite, nausea, rash, stomatitis, and vomiting. At 12 and 16 mg dose levels, dose-limiting toxicities (DLT) were observed, with an accumulation of higher-grade adverse events after the cycle 1 DLT assessment window. Pharmacodynamic findings showed pathway inhibition at ≥3 mg in patient tumor samples, consistent with preclinical PIK3CA-mutant tumor xenograft models. Confirmed response rate was 36% for PIK3CA-mutant tumor patients with measurable disease [5/14: 4 breast cancer (3 patients at 12 mg); 1 non–small cell lung cancer], where responses started at 3 mg, and 0% in patients with tumors without known PIK3CA hotspot mutations (0/15). Significance: Preliminary data consistent with preclinical data indicate increased antitumor activity of taselisib in patients with PIK3CA-mutant tumors (in comparison with patients with tumors without known activating PIK3CA hotspot mutations) starting at the lowest dose tested of 3 mg, thereby supporting higher potency for taselisib against PIK3CA-mutant tumors. Cancer Discov; 7(7); 704–15. ©2017 AACR. See related commentary by Rodon and Tabernero, p. 666. This article is highlighted in the In This Issue feature, p. 653

TPS511 Background: Despite decades of basic and clinical research, effective therapy for the treatment of patients with pancreatic ductal adenocarcinoma (PDAC) remains one of the greatest unmet clinical needs in oncology today. Albumin-bound paclitaxel (AP) and gemcitabine (G) reported on an improvement in overall survival in metastatic (m) PDAC [NEJM 2013; 369:1691-1703]. The addition of cisplatin (C) has shown promising clinical data in previously reported studies [Cancer Res 2015; 75(15 Suppl):Abstract nr LB-003]. Through further preclinical work, vitamin D analog therapy decreases myeloid derived suppressor cell (MDSC) and regulating T cells (Tregs) thus turning PDAC into a more immune friendly microenvironment. This trial combines AP/C/G with the vitamin D analog paricalcitol (P) and the antibody-PD-1 drug Nivolumab (N) as a combination therapy for individuals with previously untreated metastatic PDAC. This trial evaluates the efficacy and safety of NAPPCG in patients in that population (NCT02754726). Methods: Key eligibility criteria include Stage IV PDAC, no prior chemotherapy for systemic disease, KPS ≥ 70; life expectancy ≥ 12 weeks and measurable disease. Key exclusion criteria include prior PD-1 or PD-L1 therapy. Doses are AP 125 mg/m2 undiluted, G 1000 mg/m2 in 500 ml of normal saline (NS), each infused over 30 minutes with C 25mg/ m2 in 500 ml of NS infused over 60 minutes on days 1, 8, 22, and 29 of a 42 day cycle. N is given at a fixed dose of 240 mg as a 60 minute infusion on days 1, 15, and 29. P is given at a fixed dose of 25 µg IV on days 1,4,8,12,15,22,26,29,32,36,and 39. Primary objective is to determine the efficacy of the combination NAPPCG for patients with previously untreated metastatic PDAC through determining CR, ORR, PFS, and OS. The secondary objective is to evaluate the safety of NAPPCG in patients with previously untreated metastatic PDAC. The study initiated accrual in April of 2016. If 4 of the first 10 patients are determined to have a PR the trial will expand to a total of 25 patients. Clinical trial information: NCT02754726.

359 Background: GA, FOLFIRINOX and FOLFIRI are standard chemotherapy (CTX) regimens for mPC.The optimal introduction of these regimens following GA is not known. This phase II study evaluated 2 different approaches to this question. Methods: Eligibility criteria included 1) untreated mPC, 2) ECOG PS 0/1, 3) organ function adequate for Rx. Patients (pts) were treated according to one of 2 methods following GA given per standard dose/schedule: FOLFIRINOX (bolus 5-FU omitted) for up to 12 cycles at 24 weeks or at time of disease progression (S); or GA alternating with FOLFIRI q8 weeks up to 48 weeks total Rx (A). Results: 54 evaluable pts (28S, 26A) were enrolled . Pt characteristics included median age 65, M/F 48/52% , liver involvement 89%. 17/53 pts (31%) did not achieve disease control at 8 weeks (8 toxicity/complications , 6 disease progression, 3 declined further protocol therapy). Of the remaining 37 pts, 24/13 were treated with S/A regimens, respectively. Grade ≥ 3 treatment toxicities reported while on study with frequency ≥ 10% included anemia 21%, neutropenia 43%, thrombocytopenia 15%, and fatigue 22%. Grade ≥ 3 neuropathy occurred in 8% of pts. For all 54 pts using RECIST 1.0, CR/PR/SD/DC was 2 (4%)/20 (37%)/19 (35%)/41(76%). Ca19.9 response ≥ 90% was seen in 20/37 (54%). For all pts, median OS was 12.3 months ( 95% CI 8.6-14.5 mo); 12 and 24 mo OS was 51% and 11%, respectively. For the 37 pts with DC on GA at 8 weeks (calculated from start Rx) median OS was 13.5 mo (95% CI 10.7-15.4 mo); 12 and 24 mo OS was 55% and 16% , respectively. No statistically significant differences were seen between S and A with respect to toxicity, response or survival. Conclusions: 1) As opposed to introduction of 5FU-based CTX at the time of disease progression/prohibitive toxicity, introduction prior to that time may be at least comparable regarding both toxicity and OS. 2) This approach may further enhance OS in pts who achieve DC on GA at 8 weeks. 3) Neither S nor A method of 5FU-based CTX introduction following GA was clearly superior in this study. 4) How best to combine 5FU-based combination CTX following GA in mPC merits further study. Supported by the Seena Magowitz Foundation.

341 Background: Genomes of metastatic pancreatic cancers frequently contain intrachromosomal aberrations indicating DNA repair abnormalities associated with sensitivity to DNA damaging agents such as the platinums. Cisplatin was added to a nab-paclitaxel + gemcitabine regimen, which has been determined to improve survival over gemcitabine alone (NEJM 2013; 369:1691-1703). The objectives are to determine the efficacy and safety of nab-paclitaxel and gemcitabine plus cisplatin in patients with Stage IV pancreatic cancer. Methods: Eligibility criteria included Stage IV adenocarcinoma of the pancreas, no prior chemotherapy for systemic disease, KPS ≥ 70; life expectancy ≥ 12 weeks and measurable disease. Doses are nab-paclitaxel 125 mg/m2 undiluted, gemcitabine 1000 mg/m2 in 500 ml of normal saline (NS), each infused over 30 minutes on days 1 and 8 of a 21 day cycle, along with 3 different dose levels of cisplatin (25, 37.5 or 50 mg/m2) in 500 ml of NS infused over 60 minutes, after the nab-paclitaxel infusion. Pre and post cisplatin hydration was given. The maximum tolerated dose and phase II dose of cisplatin is 25 mg/m2. Results: 25 pts were treated; 24 were evaluable (baseline and ≥ 1 follow up CT scan). The most common drug related grade (gr) 3 - 4 adverse events (AEs), n = 25, were thrombocytopenia 76% (gr 3 = 36%, gr 4 = 40%) with no serious bleeding events, anemia 32% (gr 3 = 32%, gr 4 = 0%), neutropenia 24% (gr 3 = 20%, gr 4 = 4%), infection 20% (gr 3 = 16%, gr 4 = 4%), and diarrhea 16% (gr 3 = 16%, gr 4 = 0%). Peripheral neuropathy ≥ gr 3 was seen in only 1 pt (gr 3 = 4%). Grade 5 AEs were infection (1), cardiac arrest (1), and stroke (1). Median time on therapy was 5.5 months, range (1 – 9.5). By RECIST 1.1 criteria, 2 pts had complete response (8.3%), 15 partial response (62.5%), 4 stable disease (16.7%), and 3 progressive disease (12.5%). Median overall survival to date as of 11/10/16 is 16.5 months. Conclusions: Although a small study, the high response rate and landmark evolving median survival are very encouraging. This regimen is being expanded in patients with stage IV pancreatic cancer, neoadjuvant and adjuvant settings. Clinical trial information: NCT01893801.

249 Background: HA, a glycosaminoglycan in the tumor matrix, accumulates in 20-30% of solid tumors and ≥28%, ≥42% and ≥87% of colon, gastric and pancreatic ductal adenocarcinoma (PDA) tumors, respectively. Tumors that accumulate HA can develop high interstitial fluid pressure (IFP) and are resistant to chemotherapy. HA in human PDA is associated with disease progression and poor prognosis. In animal models, PEGPH20 reduced tumor-associated HA, tumor IFP and tumor growth, and increased efficacy of chemotherapy. Pharmacodynamic (PD) activity of PEGPH20 is being evaluated in Phase 1 (Ph1) trials. Methods: Two Ph1 studies in pts with advanced solid tumors refractory to prior therapy examined the safety, tolerability, PK, PD and MTD of single-agent IV PEGPH20. Dosing in Study 1 was 2x/wk and then reduced to q21d and in Study 2 is 1-2x/wk x 4wks and 1x/wk thereafter with dexamethasone pre-medication regimen. Biomarkers evaluated: Histochemistry to detect depletion of tumor HA, serum HA catabolites, Dynamic Contrast Enhanced (DCE)-MRI and FDG-PET. Results: In Study 1, the first 3 pts demonstrated musculoskeletal events (MSE; 2 pts dosed with 50 µg/kg 2x/wk, severe; 1 pt dosed with 0.5µg/kg 2x/wk, moderate) not predicted from GLP safety studies. The frequency of drug administration was reduced to q21d and the next 10 pts tolerated ≤1.5 µg/kg. In Study 2, dexamethasone pre-medication regimen was evaluated while dosing at 1-2x/wk. Nine pts were dosed ≤5.0 µg/kg. Doses ≤3.0 µg/kg administered 2x/wk were tolerated with intermittent Grade 1-2 MSE. Activity of PEGPH20 was reflected by increased HA serum catabolites. Pre- and post-dose biopsies from 2 colon pts demonstrated a 23-60% reduction in tumor HA after 4 wks of PEGPH20 dosing. DCE-MRI of PDA and FDG-PET of lung metastases increased tumor perfusion (Ktrans) and decreased metabolic activity 8 and 24hrs post-PEGPH20 dose and was still apparent after 4 wks of treatment with PEGPH20. Conclusions: Ongoing Ph1 studies have shown in vivo activity of PEGPH20 through HA plasma catabolites, tumor HA depletion, DCE-MRI and FDG-PET.

Abstract Purpose: First-in-human phase I trial to determine the safety, pharmacokinetics, and antitumor activity of BIND-014, a novel, tumor prostate-specific membrane antigen (PSMA)–targeted nanoparticle, containing docetaxel. Experimental Design: Patients with advanced solid tumors received BIND-014 every three weeks (n = 28) or weekly (n = 27), with dose levels ranging from 3.5 to 75 mg/m2 and 15 to 45 mg/m2, respectively. Results: BIND-014 was generally well tolerated, with no unexpected toxicities. The most common drug-related toxicities (&gt;20% of patients) on either schedule included neutropenia, fatigue, anemia, alopecia, and diarrhea. BIND-014 demonstrated a dose-linear pharmacokinetic profile, distinct from docetaxel, with prolonged persistence of docetaxel-encapsulated circulating nanoparticles. Of the 52 patients evaluable for response, one had a complete response (cervical cancer on the every three week schedule) and five had partial responses (ampullary adenocarcinoma, non–small cell lung, and prostate cancers on the every-three-week schedule, and breast and gastroesophageal cancers on the weekly schedule). Responses were noted in both PSMA-detectable and -undetectable tumors. Conclusions: BIND-014 was generally well tolerated, with predictable and manageable toxicity and a unique pharmacokinetic profile compared with conventional docetaxel. Clinical activity was noted in multiple tumor types. The recommended phase II dose of BIND-014 is 60 mg/m2 every three weeks or 40 mg/m2 weekly. Clin Cancer Res; 22(13); 3157–63. ©2016 AACR.